Flaming Gorge Technical Working Group Proposed Flow … FGTW… · Water Year 2014 Introduction...

U.S. Department of the Interior May 2014 Bureau of Reclamation

Flaming Gorge Technical Working Group Proposed Flow and Temperature Objectives for 2014

U.S. Department of the Interior May 2014 Bureau of Reclamation

Table of Contents Introduction ............................................................................................................................................... 3

Proposed Flow and Temperature Objectives for 2014 ............................................................................. 3

Proposed 2014 Spring Flow Objectives ................................................................................................ 3

Proposed Base Flow and Temperature Objectives for Base Flows 2014 ............................................. 4

Basin Hydrology ........................................................................................................................................ 6

Green River Basin Hydrology ................................................................................................................ 6

Yampa River Basin Hydrology .............................................................................................................. 7

Probabilities of Flow Events for Spring 2014 ......................................................................................... 8

Recovery Program Research Request ..................................................................................................... 9

Record of Decision Spring Flow Objectives ............................................................................................ 11

Literature Cited ....................................................................................................................................... 12

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Proposed Flow and Temperature Objectives Water Year 2014

Introduction This proposal details the Flaming Gorge Dam 2014 operational plan and is produced pursuant to the February 2006 Record of Decision for the Operation of Flaming Gorge Dam (ROD; Reclamation 2006), the Operation of Flaming Gorge Dam Final Environmental Impact Statement (FEIS; Reclamation 2006), and 2005 Final Biological Opinion on the Operation of Flaming Gorge Dam (2005 BO; Service 2005). The Flaming Gorge Technical Working Group (FGTWG) was established pursuant to the FEIS and ROD. The ROD clarified the purpose of the FGTWG as limited to proposing specific flow and temperature targets for each year’s operations based on current year hydrologic conditions and the status of endangered fish. The FGTWG was also charged with integrating, to the extent possible, any flow requests from The Upper Colorado Endangered Fish Recovery Program (Recovery Program) into the flow proposal so that Recovery Program research could also be facilitated. Members of the FGTWG include biologists and hydrologists from the Bureau of Reclamation (Reclamation), the U.S. Fish and Wildlife Service (Service), and Western Area Power Administration (Western). This group also serves as the informal consultation body for Endangered Species Act compliance as has occurred historically and as directed by the ROD. In 2000, the Recovery Program issued Flow and Temperature Recommendations for Endangered Fishes in the Green River Downstream of Flaming Gorge Dam, (Muth et al., 2000;Flow Recommendations). The Flow Recommendations provide the basis for the proposed action outlined described and analyzed in the FEIS. The ROD implements the proposed action by modifying the operations of Flaming Gorge Dam, to the extent possible, to assist in the recovery of endangered fishes, and their critical habitat, downstream from the dam and, at the same time, maintains and continues all authorized purposes of the Colorado River Storage Project (Reclamation 2006).

Proposed Flow and Temperature Objectives for 2014

Proposed 2014 Spring Flow Objectives

For the purposes of implementing the ROD in 2014, an evaluation has been made of the current hydrologic conditions in the Upper Green River (i.e. above Flaming Gorge Dam) and Yampa River Basins. The evaluation centered on the historical unregulated inflow statistics for Flaming Gorge Dam during the period from 1963 through 2013. Based on these statistics and the May 1, 2014 final forecast of 1,320,000 acre-feet for Flaming Gorge, the hydrologic classification will be average (above median) (30% to 50% exceedance) for spring 2014. The combined April through July forecast of the Yampa

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River at Maybell and Little Snake at Lily is 1,550,000 acre-feet. This forecast would fall into the moderately wet hydrologic classification of the ROD.1 Reclamation received and provided to the FGTWG a memorandum dated March 21, 2014, from the Director of the Recovery Program providing the Research Request for 2014 Green River Spring Flows (2014 Spring Flow Request). The 2014 Spring Flow Request is that the FGTWG implement the Study Plan to Examine the Effects of Using Larval Sucker Occurrence in the Green River as a Trigger for Flaming Gorge Dam (Larval Trigger Study Plan ad hoc Committee 2012; LTSP) and is described in further detail in the Recovery Program Research Request section of this document. The May final forecast for the Upper Green is in the average (above median) classification and the Yampa River Basin is in the moderately wet hydrologic classification. April received periods of above average temperatures and significant amounts of low and mid elevation snow melted bringing river flows on the Yampa River to a seasonal peak of 9,330 cfs, which occurred on April 24, 2014. Reclamation recommends operating within the official average (above median) hydrologic classification. The LTSP outlines peak flows under the average (above median) classification measured at Jensen, Utah between 18,600 cfs and 20,300 cfs for a period between 1 to 14 days during larval drift. According to the LTSP, these flows should provide connection at all study wetlands identified in the LTSP. Flaming Gorge Dam and Reservoir is in the average (above median) classification. Reclamation understands the importance of timing releases with the emergence of larval drift in the Green River downstream of the confluence between the Green and Yampa Rivers. Based on current estimates, it is likely that larval drift will occur on the descending limb of the Yampa River hydrograph, limiting the ability of Yampa River flows to assist in meeting Jensen, Utah flows of 18,600 cfs ≥ x < 20,300 for between 1 to 14 days. Reclamation recommends operating, to the extent possible, to implement the LTSP after maintaining efforts for safety and alleviation of flooding.

Proposed Base Flow and Temperature Objectives for Base Flows 2014

After the spring flow objectives in Reach 1 and Reach 2 have been achieved, flows should be gradually reduced to achieve base flow levels by no later than July 15, 2014. Base flows in Reaches 1 and 2 should be managed to fall within the prescribed base flow ranges described in the Flow Recommendations based on the observed April through July unregulated inflow into Flaming Gorge Reservoir (Figures 1 and 2). Pursuant to the Flow Recommendations, during the August through November base-flow period, the daily flows should be within ±40% of mean base flow. During the December through February base-flow period, the daily flows should be within ±25% of the mean base flow. Additionally, the mean daily flows should not exceed 3% variation between consecutive days and daily fluctuations at Flaming Gorge Dam should produce no more than a 0.1 meter daily stage change at Jensen, Utah.

1 Appendix A illustrates the May 1, 2013, final forecast for Flaming Gorge Reservoir and the Yampa River Basin in relation to the hydrologic categories described in the Flow Recommendations.

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Additionally, the temperature of flows should be managed to be at least 18° C for 2 to 5 weeks in Upper Lodore Canyon during the beginning of the base flow period. Water temperatures in the Green River should also be managed to be no more than 5° C colder than those of the Yampa River at the confluence of the Green and Yampa Rivers for the summer period (June through August).

Figure 1 – Reach 1 Base Flow Ranges for each Hydrologic Classification as Outlined in the ROD.

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Figure 2 – Reach 2 Base Flow Ranges for each Hydrologic Classification as Outlined in the ROD.

Basin Hydrology

Green River Basin Hydrology

The May 1, 2014, final forecast of April through July unregulated inflow (current forecast) for Flaming Gorge Reservoir is 1,320,000 acre-feet (AF) (135% of 30-year average). This forecast falls at approximately 31% exceedance based on the historic unregulated inflow record (1963-2013). Figure 3 shows the current forecast in relation to the historic unregulated inflow volumes.

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Figure 3 – Flaming Gorge Reservoir May final forecast and ranked historic unregulated April through July inflow volume for years 1963-2013. As of May 1, 2013, Flaming Gorge Reservoir had a water surface elevation of approximately 6019.8 feet above sea level. There is approximately 2.973 million acre-feet of live storage (79% storage capacity) in Flaming Gorge and approximately 0.77 million acre-feet of space.

Yampa River Basin Hydrology

The combined current forecast for Yampa River at Deerlodge is 1,550,000 AF (125% of 30-year average). This forecast falls at approximately 29% exceedance based on a ranking of the historic record (1922-2013). Figure 4 below shows the current forecast in relation to historic flow volumes.

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Figure 4 – Yampa River Basin (Maybell plus Lily) current forecast and ranked historic unregulated April through July inflow volume for years 1922-2013. Hydrologic conditions in the Yampa River Basin are moderately wet, although significant amounts of low and mid elevation snowpack has already melted and spring runoff conditions will likely have a significant effect on the efficiency of the 2014 spring peak.

Probabilities of Flow Events for Spring 2014

The Flaming Gorge unregulated inflow and Yampa River forecasts are average (above median). An analysis was completed to assist in the determination of appropriate flow objectives for spring and summer 2014. The ten most similar historic years for the Yampa River Basin (Maybell plus Lily) compared to the current forecast (Table 1) were analyzed assuming a normal distribution. Table 2 presents the percent exceedance of cumulative days greater than or equal to various flow levels at Yampa River (Maybell plus Lily). The Yampa River has achieved flows above 10,000 cfs this year. It is likely that the Yampa River peak will occur prior to the current estimate of larval drift.

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Table 1 Yampa River (Maybell plus Lily) – April through July Unregulated Volume

Ten Similar Years to the May 1, 2014 Final Forecast Thousand Acre-Feet (KAF)

Table 2 Spring 2013 – Days above Specific Flow Thresholds in the Yampa River (Maybell plus Lily)

Based on the May 1, 2014, Final Forecast Percent Exceedance (%)

Recovery Program Research Request Reclamation received and provided to the FGTWG a memorandum dated March 21, 2014, from the Recovery Program outlining the program’s research request for 2014 Green River spring flows (2014 Spring Flow Request). The Recovery Program requests that the FGTWG implement the LTSP by matching Recovery Program research needs identified in the LTSP with the best available spring flow forecast information to develop a specific Reach 2 floodplain connection scenario. The LTSP describes a range of floodplain scenarios

Year

April-July Unreg Inflow

Volume (KAF)

MIN 1,1401968 1,4201938 1,4391958 1,443

1975 1,4501947 1,479

MOST 1,5001945 1,514

1973 1,5271993 1,5431979 1,5621965 1,564

MAX 1,950

May Final Forecast % Exceed

Days above 8,000 cfs


Days above

10,000 cfsDays above 11,000 cfs




25% 47 39 32 25 19 13 1050% 41 32 26 19 14 10 775% 36 31 22 17 13 9 590% 34 27 21 15 11 5 4

YAMPA

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that they would like to study and how they would evaluate the results. Additionally, the 2014 Spring Flow Request’s primary objective is to build on past research to benefit the razorback sucker population throughout the Green River by timing the river-floodplain connection with the presence of wild-produced razorback sucker larvae. The 2014 Spring Flow Request supports operations consistent with the 2005 BO and ROD; however, it differs from the ROD in matching the timing and duration of Flaming Gorge releases with the spring peak flows from the Yampa River. Therefore, the ability to meet the Reach 2 flow targets at Jensen, Utah, is comprised. Table 3 is a copy of the matrix found in Table 2 of the LTSP. It describes the flow conditions and corresponding wetlands. Under average (above median) conditions, at least eight wetlands should be available for sampling including larval fish collection and/or fall young-of-year fish collection (Table 3). Recovery Program investigators anticipate that a large fraction of these habitats will be sampled to some extent during 2014, which will enable evaluation of larval entrainment under average (above median) hydrologic conditions. Results of larval fish collection in the spring from individual wetlands will help determine the extent of fall young-of-year sampling in those areas. The LTSP experimental timetable is to achieve three years of flows at Jensen, Utah, below 18,600 cfs, and three years above 18,600 cfs, with connecting flows in each of these years of at least seven days duration. However, spring peak flow magnitudes will be driven by hydrologic conditions in the Upper Green River Basin; it may not be possible to complete the experiment in six consecutive years.

Table 3 – LTSP TABLE 2. Matrix to Be Used in Studying the Effectiveness of a Larval Trigger Peak Flow (x) as Measured at Jensen, Utah Potential Study Wetlands(a,b)

Number of Days (x) Flow Exceeded and Corresponding Hydrologic Conditions (c)

1 ≤ x < 7 7 ≤ x < 14 x ≥14 8,300 < x < 14,000 cfs Stewart Lake (f), Above Brennan

(f), Old Charley Wash (s) Dry Moderately

dry Moderately dry and average (below median)

14,000 ≤ x < 18,600 cfs

Same as previous plus Escalante Ranch (f), Bonanza Bridge (f), Johnson Bottom (s), Stirrup (s), Leota 7 (s)

Average (below median)



18,600 ≤ x < 20,300 cfs

Same as previous Average (above median)

Average (above median)

Average (above median)

20,300 ≤ x < 26,400 cfs

Same as previous plus Baeser Bend (s), Wyasket (s), additional Leota units (7a and 4), Sheppard Bottom (s)

Moderately wet

Moderately wet

Moderately wet

x ≥ 26,400 cfs Same as previous Wet Wet Wet f = flow-through wetland, s = single-breach wetland

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Record of Decision Spring Flow Objectives The FEIS specifically addresses the content of this operating plan in Section 2.5.3.1. The operating plan is to describe the current hydrologic classification of the Green River and Yampa River Basins, including the most probable runoff patterns for the two basins. This information has been provided above. The operating plan is also to identify the most likely Reach 2 flow magnitudes and durations that are to be targeted for the upcoming spring release. It further specifies that “[b]ecause hydrologic conditions often change during the April through July runoff period; the operations plan would contain a range of operating strategies that could be implemented under varying hydrologic conditions. Flow and duration targets for these alternate operating strategies would be limited to those described for one classification lower or two classifications higher than the classification for the current year.” Flaming Gorge Reservoir unregulated inflow forecast for April through July falls between 764,000 AF and 1,328,000 AF, the hydrological classification is average. The peak flow as measured at Jensen, Utah, would correspond with the average hydrologic condition with targeted flows of ≥ 8,300 cfs in Reach 2 for a duration of at least one week. ROD spring flow objectives for average years are:

Table 5 – Average Spring Flow Objectives

Reach Spring Peak Magnitude

(cfs) Spring Peak Duration

Reach 1 ≥ 4,600 cfs That necessary to achieve duration target in

Reach 2

Reach 2

≥ 18,600 cfs in 50% of average years

Two weeks (i.e. 14 days) in 25% of all average years

≥ 8,300 cfs in 50% of average years

One week (i.e. 7 days) in 50% of average years

Source: Flow Recommendations and FEIS

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Literature Cited Bureau of Reclamation. 2005. Operation of Flaming Gorge Dam Final Environmental Impact Statement. U.S. Department of the Interior, Bureau of Reclamation, Salt Lake City, Utah. Bureau of Reclamation. 2006. Record of Decision on the operation of Flaming Gorge Dam Final Environmental Impact Statement. U.S. Department of the Interior, Bureau of Reclamation, Salt Lake City, Utah. Larval Trigger Study Plan ad hoc Committee. 2012. Study Plan to Examine the Effects of Using Larval Razorback Sucker Occurrence in the Green River as a Trigger for Flaming Gorge Dam Peak Releases. U.S. Fish and Wildlife Service, Upper Colorado River Endangered Fish Recovery Program, Denver, Colorado. Muth, R.T., L.W. Crist, K.E. LaGory, J.W. Hayse, K.R. Bestgen, T.P. Ryan, J.K. Lyons, and R.A. Valdez. 2000. Flow and temperature recommendations for endangered fishes in the Green River downstream of Flaming Gorge Dam. Final Report to Upper Colorado River Endangered Fish Recovery Program, Denver, Colorado. Upper Colorado River Endangered Fish Recovery Program. March 21, 2014. Memorandum to Larry Walkoviak and Heather Patno. Recovery Program Research Request for 2014 Green River Spring Flows. U.S. Fish and Wildlife Service, Upper Colorado River Endangered Fish Recovery Program, Denver, Colorado.

APPENDIX A May 1, 2014 Final Forecasted April through July Inflow Volumes

for Flaming Gorge Reservoir and Yampa River at Deerlodge

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APPENDIX A May 1, 2014 Final Forecasted April through July Inflow Volumes

for Flaming Gorge Reservoir and Yampa River at Deerlodge

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APPENDIX B Recovery Program’s Research Request for 2014 Green River Spring Flows

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Flaming Gorge Technical Working Group Proposed Flow … FGTW… · Water Year 2014 Introduction...

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